200 ( HAPTER 14 



\l tiller. H. J.. "The Nature oi the Genetic Effects Produced by Radiation," in Radiation 

 Biology, Hollaender, A. (Ed.), Vol. I. Chap. 7:351 473. New York: McGraw- 

 Hill, l l >54. 



Mul lor. H. J., and Oster, I. I.. "Some Mutational Techniques in Drosophila," pp. 249- 

 278. in Methodology in Basic Genetics, Burdette, W. J. (Ed.). San Francisco: 

 Holden-Day, 1963. 



Schalet, A.. "A Study of Spontaneous Visible Mutations in Drosophila Melanogaster," 

 Proc. X Intern. Congr., Genetics. Montreal. 2:252 (Abstr.), 1958. 



See Supplement 111. 



QUESTIONS FOR DISCUSSION 



14.1. Is there a safe dose of X rays and/or ultraviolet radiation; that is, a dose that 

 cannot produce some point mutations? Explain. 



14.2. Can we he sure that any given mutation involves a single gene change rather 

 than intergenic one? Explain. 



14.3. Would we know of the existence of genes if all genes had identical mutational 

 capacity? Explain. 



14.4. Would you expect the mutation rate to Polydactyly, P, from normal, /?, to be 

 greater among normal individuals in a pedigree for Polydactyly than it is among 

 normals in general? Explain. How might you test your hypothesis? 



14.5. Do the mutational properties discussed suggest any limitations with respect to 

 the chemical composition of genes? Explain. 



14.6. When a chromosome is broken, is the breaking point within a gene, between 

 genes, or both? Justify your answer. 



14.7. Point mutations are sometimes called gene mutations. Do you think this is 

 permissible? Why? 



14.8. In what way is the study of mutation dependent upon genes? In what way 

 is the reverse true? 



14.9. What is your opinion regarding the validity of applying principles of point 

 mutation directly to gene mutation? 



14.10. Are all of the mutants detected by the Base or Maxy techniques point mutants? 

 Explain. 



14.11. Suppose, in the Base technique, an F 2 culture produced both of the expected 

 t\pes of daughters but no sons at all. To what would you attribute this result? 



14.12. How can you determine whether a recessive lethal detected in the F L > by the 

 Base technique is associated with an inversion or a reciprocal translocation? 



14.13. A wild-type female produces 110 daughters but only 51 sons. How can you 

 test whether this result is due to the presence, in heterozygous condition, of a 

 recessive X-linked lethal? 



14.14. How can you explain the phenotype of a rare female in the Maxy stock that 

 produces only unexceptional progeny but has compound eyes distinctly lighter 

 than normal? 



14.15. Compare the relative suitability of man and Drosophila for the determination 

 of mutation frequencies. 



14.16. The genes in the X chromosomes are incompletely linked in the females of 

 the Base stock. Do you agree with this statement? Why? 



